Shrink wrap is used for a multitude of applications from wrapping produce in supermarkets to covering containers and products for shipping. For the purpose of this description product and container are used interchangeably as examples of the use of the invention. The shrink wrap film will deform with the application of heat to surround snugly the product or product container to be protected. However, shrink wrap is subject to tears, rips and punctures and has no more strength than the film itself.
Reinforced plastic films have been developed that are durable, strong and resist punctures and tearing. An example is U.S. Pat. No. 4,592,941 assigned to the applicant which is incorporated by reference herein as part of the specification of this application. The reinforced plastic film is used to make bags for heavy products, storage and outdoor coverings as described in its specification. However, it does not deform in a shrink wrap manner upon exposure to heat to snugly fit to cover the product or container.
The present invention is a reinforced shrink wrap that can be made to cover all sizes of products and containers and is especially suited for covers for large equipment. The reinforced shrink wrap is multilayered and includes a reinforcing grid with the shrink layer. The reinforced shrink wrap is superior to the conventional non-reinforced product for packaging, handling, shipping and storage of goods. The reinforcing grid minimizes and contains tears, rips and prevents punctures from spreading. Yet, the multilayered reinforced shrink wrap deforms to fit the product or container in the same or similar manner as the conventional shrink wrap.
The multilayered shrink wrap has at least one layer of shrink film of highly irradiated polyethylene. On either side of the shrink film is reinforcing filamentous grid in a flexible adhesive layer. On the outer surfaces of the multilayer reinforced shrink wrap are two layers of polyolefin film. The reinforced shrink wrap may have more than one inner layer of shrink film with additional facing layers of the filamentous reinforcing grid in the adhesive layer. Also, inner layers of polyolefin film may be added with the reinforcing grid and adhesive layers facing either side of the inner polyolefin layer. The polyolefin layers may be a multiply film.
Additives used in polyolefin film may be included as desired in the polyolefin inner or outer layers or in one of more plies of a multiply film. Additives include ultraviolet light stabilizers, flame retardants, static inhibitors, antioxidants, color additives, corrosion inhibitors, biocides and compatible mixtures of the additives as desired.
The reinforced shrink wrap is resistant to localized heat burn through during the heating step used to shrink the wrap around the product. The use of the reinforced shrink wrap is particularly suited for protecting cargo and equipment exposed to harsh environments.